Amateur or professional swimmers, as well as subaqueous swimmers, actually use flippers which are applied only to the feet. These flippers are directly put on the feet or they form a single body with shoes to be applied to the feed. Consequently, the surface or membrane of the specific flipper, with no regard to the material out of which it is made, (rubber, more or less hard plastic, resin, etc.), remains always rigid with respect to the foot. This forces the swimmer to move and to walk in the water keeping his legs rigid, without bending his knees, and moving his legs alternatively and rhythmically. The resulting movement is not very quick.
Observing nature, and particularly the way of moving of water animals and birds, it has been noted that all these animals use, for their moving, limbs which are flexible or which they can draw back: flippers, or feet provided with membranes, for water animals; and wings for birds. Both limbs work exactly in the same way. They reduce to a minimum the friction surface in the passive stage, increasing the same to a maximum during the active stage, i.e. during the push stage. If there were not a difference in the friction surface of the moving limbs, between the active and the passive stage, there would not be any forward movement.
The same phenomenon can be observed in the case of oars of a boat. The rower submerges the oars in the water to give a thrust or push to the boat and then lifts the oars out of the water to return them to their initial position. If the oars were left in the water during the recovery or passive stage of the return of oars to their initial position, no net thrust would result and the boat would not move. In such a case, the oars would function as flippers with a rigid surface wherein the active or thrust stage would be equal to the passive or recovery stage and there would be no net movement through the water. However, when properly used, the oars are caused to provide the same function or result as a flipper with a variable surface by being lifted out of the water in the passive or recovery stage so that they provide no surface to the water during this stage, and therefore no thrust in the opposite direction to that in which the thrust is provided during the active stage.
The present invention eliminates all inconveniences and disadvantages of the prior flippers for swimmers and assures to the swimmer an optimal forward movement in the water. There are provided flippers which, when applied to the limbs (feet and hands), allow the swimmer to exploit all his energy, with movements which are natural for the human body, adapted for this purpose, as the lifting and immersing of the foot, with bending and extending of the leg, and the articulated movements of the arms.